
var forEachPoint = function (func) {
    return function (input, opt_output, opt_dimension) {
        var len = input.length;
        var dimension = opt_dimension ? opt_dimension : 2;
        var output;
        if (opt_output) {
            output = opt_output;
        } else {
            if (dimension !== 2) {
                output = input.slice();
            } else {
                output = new Array(len);
            }
        }
        for (var offset = 0; offset < len; offset += dimension) {
            func(input, output, offset);
        }
        return output;
    };
};
var gcj02 = {};
var i = 0;
var PI = Math.PI;
var AXIS = 6378245.0;
var OFFSET = 0.00669342162296594323; // (a^2 - b^2) / a^2

function delta(wgLon, wgLat) {
    var dLat = transformLat(wgLon - 105.0, wgLat - 35.0);
    var dLon = transformLon(wgLon - 105.0, wgLat - 35.0);
    var radLat = (wgLat / 180.0) * PI;
    var magic = Math.sin(radLat);
    magic = 1 - OFFSET * magic * magic;
    var sqrtMagic = Math.sqrt(magic);
    dLat =
        (dLat * 180.0) / (((AXIS * (1 - OFFSET)) / (magic * sqrtMagic)) * PI);
    dLon = (dLon * 180.0) / ((AXIS / sqrtMagic) * Math.cos(radLat) * PI);
    return [dLon, dLat];
}

function outOfChina(lon, lat) {
    if (lon < 72.004 || lon > 137.8347) {
        return true;
    }
    if (lat < 0.8293 || lat > 55.8271) {
        return true;
    }
    return false;
}

function transformLat(x, y) {
    var ret =
        -100.0 +
        2.0 * x +
        3.0 * y +
        0.2 * y * y +
        0.1 * x * y +
        0.2 * Math.sqrt(Math.abs(x));
    ret +=
        ((20.0 * Math.sin(6.0 * x * PI) + 20.0 * Math.sin(2.0 * x * PI)) *
            2.0) /
        3.0;
    ret +=
        ((20.0 * Math.sin(y * PI) + 40.0 * Math.sin((y / 3.0) * PI)) * 2.0) /
        3.0;
    ret +=
        ((160.0 * Math.sin((y / 12.0) * PI) +
            320 * Math.sin((y * PI) / 30.0)) *
            2.0) /
        3.0;
    return ret;
}

function transformLon(x, y) {
    var ret =
        300.0 +
        x +
        2.0 * y +
        0.1 * x * x +
        0.1 * x * y +
        0.1 * Math.sqrt(Math.abs(x));
    ret +=
        ((20.0 * Math.sin(6.0 * x * PI) + 20.0 * Math.sin(2.0 * x * PI)) *
            2.0) /
        3.0;
    ret +=
        ((20.0 * Math.sin(x * PI) + 40.0 * Math.sin((x / 3.0) * PI)) * 2.0) /
        3.0;
    ret +=
        ((150.0 * Math.sin((x / 12.0) * PI) +
            300.0 * Math.sin((x / 30.0) * PI)) *
            2.0) /
        3.0;
    return ret;
}

gcj02.toWGS84 = forEachPoint(function (input, output, offset) {
    var lng = input[offset];
    var lat = input[offset + 1];
    if (!outOfChina(lng, lat)) {
        var deltaD = delta(lng, lat);
        lng = lng - deltaD[0];
        lat = lat - deltaD[1];
    }
    output[offset] = lng;
    output[offset + 1] = lat;
});

gcj02.fromWGS84 = forEachPoint(function (input, output, offset) {
    var lng = input[offset];
    var lat = input[offset + 1];
    if (!outOfChina(lng, lat)) {
        var deltaD = delta(lng, lat);
        lng = lng + deltaD[0];
        lat = lat + deltaD[1];
    }
    output[offset] = lng;
    output[offset + 1] = lat;
});

var sphericalMercator = {};

var RADIUS = 6378137;
var MAX_LATITUDE = 85.0511287798;
var RAD_PER_DEG = Math.PI / 180;

sphericalMercator.forward = forEachPoint(function (
    input,
    output,
    offset
) {
    var lat = Math.max(
        Math.min(MAX_LATITUDE, input[offset + 1]),
        -MAX_LATITUDE
    );
    var sin = Math.sin(lat * RAD_PER_DEG);

    output[offset] = RADIUS * input[offset] * RAD_PER_DEG;
    output[offset + 1] = (RADIUS * Math.log((1 + sin) / (1 - sin))) / 2;
});

sphericalMercator.inverse = forEachPoint(function (
    input,
    output,
    offset
) {
    output[offset] = input[offset] / RADIUS / RAD_PER_DEG;
    output[offset + 1] =
        (2 * Math.atan(Math.exp(input[offset + 1] / RADIUS)) - Math.PI / 2) /
        RAD_PER_DEG;
});

var projzh = {};
projzh.ll2gmerc = function (input, opt_output, opt_dimension) {
    let output = gcj02.fromWGS84(input, opt_output, opt_dimension);
    return projzh.ll2smerc(output, output, opt_dimension);
};
projzh.gmerc2ll = function (input, opt_output, opt_dimension) {
    let output = projzh.smerc2ll(input, input, opt_dimension);
    return gcj02.toWGS84(output, opt_output, opt_dimension);
};
projzh.smerc2gmerc = function (input, opt_output, opt_dimension) {
    let output = projzh.smerc2ll(input, input, opt_dimension);
    output = gcj02.fromWGS84(output, output, opt_dimension);
    return projzh.ll2smerc(output, output, opt_dimension);
};
projzh.gmerc2smerc = function (input, opt_output, opt_dimension) {
    let output = projzh.smerc2ll(input, input, opt_dimension);
    output = gcj02.toWGS84(output, output, opt_dimension);
    return projzh.ll2smerc(output, output, opt_dimension);
};

projzh.ll2smerc = sphericalMercator.forward;
projzh.smerc2ll = sphericalMercator.inverse;

export default projzh